Post-launch dual pressure sensitive arming device

ABSTRACT

A fuze for preventing warhead initiation in an air launched guided missile until a safe separation distance has been achieved between the missile and launching aircraft. To achieve this separation distance a spring loaded air scoop is allowed to popup into the missile air stream to provide dynamic air pressure to a bellows actuated escapement mechanism which controls the amount of delay.

United States Patent Hoelzen et a1.

[ Dec. 23, 1975 POST-LAUNCH DUAL PRESSURE SENSITIVE ARMING DEVICE Inventors: Warren R. Hoelzen, Ontario;

Charles R. Hamilton, Riverside;

James E. Warnock, La Mirada, all of Calif.

The United States of America as represented by the Secretary of the Navy, Washington, DC.

Filed: Jan. 22, 1969 Appl. No.: 795,771

Assignee:

US. Cl 102/82; 102/81 Int. Cl. F42C 9/00 Field of Search 102/82, 81, 81.2, 83, 84,

References Cited UNITED STATES PATENTS 6/1961 Leonard et a1. [OZ/81.2 X

MISSILE 3,170,404 2/1965 Swaim et a1. 102/84 3,229,638 l/1966 Woolston et a1 102/81 X 3,358,605 12/1967 Ayers 102/81 3,366,008 H1968 Grandy.... 89/1.5 D 3,382,805 5/1968 Swaim 102/86 X 3,568,602 3/1971 Warren 102/81 Primary Examiner-Verlin R. Pendegrass Assistant ExaminerHaro1d Tudor Attorney, Agent, or FirmR. S. Scia'scia; G. J. Rubens; T. M. Phillips [57] ABSTRACT A fuze for preventing warhead initiation in an air launched guided missile until a safe separation distance has been achieved between the missile and launching aircraft. To achieve this separation distance a spring loaded air scoop is allowed to pop-up into the missile air stream to provide dynamic air pressure to a bellows actuated escapement mechanism which controls the amount of delay.

7 Claims, 3 Drawing Figures U.S. Patent Dec. 23, 1975 Sheet1of2 3,927,617

WARREN R. HOELZEN CHARLES R. HAMILTON JAMES E. WARNOCK mvzazgoRs f BY 2 3 7 ATTORNEYS US. Patent Dec.23, 1975 Sheet2of2 3,927,617

WARREN R. HOELZEN CHARLES R. HAMILTON JAMES E. WARNOCK ATTORNEYS POST-LAUNCH DUAL PRESSURE SENSITIVE ARMING DEVICE "The invention herein described may be manufactured and used by.or forthe- Government of the United States of America for governmental purposes without the payment of any royalties thereon ortherefor.

The present invention relates to a fuze for freefall weapons and more particularly to fuzes for freefall weapons which senses a condition peculiar to the missile post launch environment. Guided missile fuzes depend upon acceleration and deacceleration senses to actuate escapement mechanisms to provide a delay so that a safe distance between the launching aircraft and the missile can be achieved prior to arming the missile. Acceleration and deacceleration forces depend upon launch angle, action of the launching aircraft, etc. and are not uniform for all launches.

The present invention overcomes the disadvantages of inertia operated fuzes and provides a means for arming the fuze which is dependent upon a post launch condition. A pop-up pressure probe senses the dynamic pressure in the slip-stream of the missile. The sensed pressure is fed to a bellows actuated escapement mechanism which arms the warhead.

Many of the attendant advantages of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an assembled view of a preferred embodiment of the invention;

FIG. 2 is a detailed view of the pressure probe of FIG. 1 in the open position;

FIG. 3 is a schematic diagram showing the functional operation of the fuzing mechanism.

Referring now to the drawings there is shown in FIGS. 1 and 2 an air scoop probe which is sealed, prior to launch of the missile, in a container 12 by means of a cover 14 and screws 16. Cover 14 has a tear-away strip 18 which will tear along the line 20. Mounted on tear strip 18 is a bracket 22 and pins 24 to which a bailrod cable 26 can be attached at one end. The other end of cable 26 is attached to the missile launching bracket 28. A cable assembly 29 with a connector 30 provides pre-launch electrical energy from the launching aircraft to the missile. As the missile is launched from the parent aircraft, air pressure differential is developed in pressure probe 10 and fed by means of tubes 32 and 34 to connector assembly 36. Internal electrical energy from the missile is supplied to fuze assembly 37 by means of electric cable 38.

Referring to FIG. 4 there is shown a schematic representation of the fuze mechanism. Air pressure is transferred through sensor tubes 32 and 34 to bellows 40 and 42. The positive pressure on the forward end of probe 10 (FIG. 2) causes retracted bellows 40 to extend (as shown by arrow) and the negative pressure developed at the aft end of probe 10 simultaneously causes the extended bellows 42 to retract, thereby rotating rocker arm 44.

A bias spring 48 and a compensating spring 50 prevents movement until a predetermined level of air pressure occurs, as for example 2 lb. psi, then full movement occurs. Compensating spring 50 which may be a leaf spring (convoluted or bowed) compensates for the spring rate of the bellows and permits bellows 40 and 42 to respond only to the air pressure developed in pressure probe 10.

In operation, three sources of energy are utilized to arm the fuze: electrical energy to operate rotary solenoid 46 and release the positive lock latch; mechanical energy to tear off the protective cover 18 of the housing 12; and air pressure differential obtained by pressure probe 10 in the missile slip-stream after launch. As shown in FIG. 4 in the safe position and prior to launch, solenoid position indicator 52 in this position indicates solenoid 46 has not been activated and that latch 47 is in the locked position, indicator 54 in this position indicates that bellows 40 and 42 have not been activated, and indicator 56 in this position indicates that explosive train 58 has not moved to an armed position. When in the solenoid activated, bellows cocked condition, the condition of the solenoid and bellows are indicated by indicator 52 and 54 respectively. A pin 60 is attached to rocker arm 44 on one end and to a coiled leaf spring 62 on the other end. Spring 62 is also attached to an escapement mechanism 64 by means of pin 66. In the bellows cocked position, spring 62 has been straightened out and is under tension. Because ratchet 68 is no longer held in position by latch 47, gear wheel 65 is free to move in the direction of the arrow and is restrained only by the geneva escapement 70. This movement continues until gear wheel 65 has moved to the armed position which is indicated by indicator 56. In practice, a minimum launch velocity of Mach 0.5 and a maximum altitude of 15,000 feet, provides a sufficient differential pressure to provide energy for arming is sensed by probe 10.

We claim:

1. In an aircraft launched guided missile fuze sensitive to a post launch environment for arming, the combination comprising:

a. arming mechanism means normally in an unarmed position and having an armed position.

b. pressure sensing means being exposed to the atmosphere after the launch of the missile for sensing at least two different dynamic ram air pressures,

c. at least two pressure sensitive actuating means coupled to said arming mechanism means and to said pressure sensing means for actuating said arming mechanism means from the unarmed position to the armed position in response to a predetermined different in the level of said sensed dynamic ram air pressures.

2. In the guided missile fuze of claim 1 wherein said pressure sensing means is mounted with a first position in a pneumatically sealable container prior to launch and a second position extending beyond the surface of said container and the surface of the missile after launch.

3. In the guided missile fuze of claim 2 wherein said sealing means contains a portion of the surface of said container that is flush with the surrounding missile surface that is weakened to provide easy tear-away of that portion to permit the deployment of the pressure sending means.

4. In the guided missile fuze of claim 2 wherein said tear-away portion has bracket means mounted on the outer surface for attaching a lanyard between the missile and the launching aircraft.

5. In the guided missile fuze of claim 4 wherein said pressure sensing means is a pressure probe mounted within said sealed container and being spring loaded and held in a first position by said tear-away portion 4 pressed bellows and compression of said normally expanded bellows in response to said predetermined difference in the level of said sensed dynamic ram air pressures.

7. The guided missile fuze of claim 6 wherein said arming mechanism means includes a geneva mechanism driven by the torque force generated by said pressure sensitive actuating means.

* l l l l 

1. In an aircraft launched guided missile fuze sensitive to a post launch environment for arming, the combination comprising: a. arming mechanism means normally in an unarmed position and having an armed position, b. pressure sensing means being exposed to the atmosphere after the launch of the missile for sensing at least two different dynamic ram air pressures, c. at least two pressure sensitive actuating means coupled to said arming mechanism means and to said pressure sensing means for actuating said arming mechanism means from the unarmed position to the armed position in response to a predetermined different in the level of said sensed dynamic ram air pressures.
 2. In the guided missile fuze of claim 1 wherein said pressure sensing means is mounted with a first position in a pneumatically sealable container prior to launch and a second position extending beyond the surface of said container and the surface of the missile after launch.
 3. In the guided missile fuze of claim 2 wherein said sealing means contains a portion of the surface of said container that is flush with the surrounding missile surface that is weakened to provide easy tear-away of that portion to permit the deployment of the pressure sending means.
 4. In the guided missile fuze of claim 2 wherein said tear-away portion has bracket means mounted on the outer surface for attaching a lanyard between the missile and the launching aircraft.
 5. In the guided missile fuze of claim 4 wherein said pressure sensing means is a pressure probe mounted within said sealed container and being spring loaded and held in a first position by said tear-away portion and being of sufficient length to extend into the missile slip-stream in a second position when said restraining tear-away portion has been removed in response to tHe launching force exerted on the connecting lanyard.
 6. In the fuze of claim 1 wherein said two pressure sensitive actuating means comprises a normally compressed bellows and a normally expanded bellows mechanically linked together and providing an output torque force with the expanding of said normally compressed bellows and compression of said normally expanded bellows in response to said predetermined difference in the level of said sensed dynamic ram air pressures.
 7. The guided missile fuze of claim 6 wherein said arming mechanism means includes a geneva mechanism driven by the torque force generated by said pressure sensitive actuating means. 